The present invention relates to electric appliances, and more specifically, to an electric iron adopted to preventing the burning of fabric or ironing board surfaces when the iron is disengaged by the operator or inadvertently left unattended.
An electric clothes iron consists essentially of a heated sole plate that is pressed against fabric to remove wrinkles. To be effective, the sole plate of an iron must be very hot. Thus, there is a serious danger of burning the fabric or ironing board or even igniting a fire from an electric iron inadvertently left unattended. In addition, lifting and placing an iron on its tail can be physically straining on the operator""s wrist, especially those who suffer from arthritis. Furthermore, when the iron is placed on its tail, the hot sole plate is exposed and may cause accidental contact with the sole plate by the user can result in severe burns.
Some pre-existing flat irons have utilized tilting mechanisms, typically hinging near the base of the tail, to raise the sole plate away from the ironing board when left unattended. However, these types of flat irons are frequently unstable and exposed the hot sole plate. Furthermore, these irons generally do not provide enough separation between the sole plate and the ironing board at the tail section. Modern electric irons have base plates to allow the user to stand the iron in a vertical position away from the fabric, but the hot sole plate is still exposed to accidental contact by the user or others. Furthermore, the small base plate and vertical orientation of the standing iron makes such irons prone to falling over due to a high center of mass, which may cause the hot sole plate to inadvertently contact and damage nearby fabric or ironing board surfaces or burn hands.
To reduce the danger of burning the fabric or ironing board by an unattended iron, most electric irons have automatic shut-off devices. The automatic shut-off devices turn off power to the sole plate heater when the iron has not been used for a fixed period of time, such as 10 minutes. Although a 10-minute shut-off cycle is appropriate for avoiding long-term operation of an electric iron in the absence of use, damage may occur long before the expiration of the 10-minute timing cycle, if the sole plate of an electric iron remains stationary in contact with fabric or other surfaces susceptible to marking, charring, or other heat damage. However, reducing the timing cycle to a short enough value to avoid such damage interferes with the normal usage of the electric iron.
Various schemes have been devised to determine when the iron is in use and what timing cycle should be used. For example, some irons use motion sensors or accelerometers. When the iron is moved by the user, the motion sensor repeatedly resets the automatic shut off timer so that power will not be removed from the sole plate when the user is operating the iron. One disadvantage of this type of iron is that it automatically shuts off when held motionless by the user. Also, such an iron may not function properly on an uneven surface.
What is needed is an electric iron that avoids the disadvantages of pre-existing electric irons discussed above, that automatically raises the hot sole plate away from the fabric or the ironing board surface to prevent burning of the fabric or the ironing board surface if the iron is disengaged by the operator or inadvertently left unattended, that automatically raises the sole plate upon removal of the user""s hand or during a power outage, that prevents the burning of fabric by creating an even vertical separation between the sole plate and fabric immediately after disengagement by the operator, and that reduces the possibility of being tipped over and exposing the hot sole plate.
Accordingly, the present invention is a clothing iron capable of lifting the sole plate of the iron away from a surface on which the iron rests when the iron is not in use. An important characteristic of the invention is that the sole plate of the iron is lifted in a direction including a substantial vertical vector, preferably with a plane of the sole plate remaining roughly horizontal. The lifting is accomplished with the use of at least one leg that extends downward from the iron to lift the sole plate.
In general, the invention comprises an actuation device, a sole plate including a top surface and a bottom surface, a housing coupled to the top surface of the sole plate, at least one leg for lifting the sole plate, and an elevation mechanism positioned within the housing capable of moving the leg to allow the sole plate of the iron to contact the horizontal surface under the sole plate. Any number, shape, and size of legs may be used, although two legs are used in some preferred embodiments. The legs may extend from beside the sole plate of the iron, or through apertures in the sole plate of the iron, or any combination thereof. In some embodiments the legs may be extended and withdrawn in a motion along a vertical axis, or in other embodiments, the legs may be rotated up and down as desired. When retracted, the legs are preferably withdrawn into the housing of the iron. In other embodiments, the leg may retract into a perforated surface that extends from the sole plate. Preferred characteristics of the selected leg configuration include resistance to tipping, and the provision of sufficient space between the support surface and the underside of the iron. The extended legs also act as a sole plate guard, in the event the iron is tilted on its side the legs may prevent accidental contact with the exposed sole plate. A sensor is preferably located in the handle of the iron capable of perceiving when a user has gripped the handle of the iron. Virtually any known and acceptable sensors may be used. In alternate embodiments, additional sensors may be used, and the sensors may be positioned in places other than the handle.
In one preferred embodiment, the elevation mechanism comprises a lift plate with a top side and a bottom side. The legs are coupled to the bottom side of the lift plate. The lift plate is preferably capable of moving up and down along a path or vector including a substantial vertical element. The lift plate is preferably biased downward so that the legs are normally extended. Thus, when the power to the iron is off, or when the user is not in contact with the handle of the iron, the legs are extended. In a preferred embodiment, the downward bias is provided by one or more springs in contact with the lift plate. A means for overcoming the downward bias of the lift plate is coupled to the lift plate so that when the sensor perceives that the user has grasped the handle of the iron, the elevation mechanism is activated and the legs are pulled up into the housing. This allows the sole plate may contact the support surface. In a preferred embodiment, the means for overcoming the downward bias is at least one geared stepper motor that, when supplied with power, will generate a larger force than that of the biased springs causing the lift plate to bias upwards. When the power to the geared stepper motor is disconnected, the spring force preferably will cause the lift plate to bias downward.
In a preferred embodiment, the tail comprises a slight rounded edge. This tail configuration is preferably capable of allowing the sole plate to slide over buttons or uneven sections of fabric. Virtually any shape of the tail that allows smooth transition of the sole plate over uneven surfaces may be used.